By Jack Fink, CBS 11 NewsBy Jack Fink

ARLINGTON (CBSDFW.COM) – On Tuesday night, authorities say that Barnes Nettles shot and killed his ex-girlfriend, Kimberly Carter, and police officer Jillian Smith at the Arbrook Park apartment complex in Arlington, before turning the gun on himself.

Carter’s family grieves. Her stepmother, Leah Richardson, said of the 29-year-old, “We lost someone really beautiful. She was our oldest daughter.”

But court records that CBS 11 News has obtained from Washington State show that this could have been avoided. “He should have been locked up a long time ago,” Richardson said. Legal experts agree.

Nettles served 15 months in a Washington prison after being convicted for raping a child in 1997. “Nettles, because he had a felony conviction, was prohibited from ever possessing a firearm,” explained Richard Roper, the former U.S. Attorney for the northern district of Texas.

However, records show that, when previous girlfriends filed domestic violence complaints against Nettles, he threatened them with a gun. In July 2003, one woman told the King County Sheriff’s Office in Seattle that Nettles “placed a silver revolver with rubber grip to her temple. She begged him not to shoot her.”

And in March 2004, a Seattle Police Department document had reported that Nettles “was armed with a revolver that was in his pants pocket, and the victim was fully aware of his violent tendencies.”

And again in August 2004, records show that Nettles pleaded guilty to domestic violence assault, reckless driving and violation of his no-contact order. He was sentenced to one year in jail. “He could have received up to 10 years in federal prison without parole, for merely possessing a firearm,” Roper said.

Law enforcement in Washington should have referred Nettles’ case to federal ATF agents to investigate, Roper said. But prosecutors in King County told CBS 11 News that the judge did not have any substantial evidence that Nettles possessed a firearm.

However, court records show that, as part of his guilty plea, the King County judge told Nettles that he was ineligible to possess a firearm, and ordered him to immediately surrender a concealed pistol license. The documented court order was even signed by Nettles.

“It’s unfortunate that those charges weren’t pursued,” Roper said, “because that’s exactly what that felon in possession statute is designed for – so you don’t end up with a tragic case like Nettles.”

Now, years later, Carter’s family cannot help but wonder what went wrong. “There’s two families without a loved one,” Richardson said. “He don’t even get a chance to face a judge, or even us.”

But while the case fell through the cracks in Washington, Ropers does not believe that such a thing would happen here in North Texas. Area police departments, he said, including in Arlington, are very aggressive and regularly refer violent felons to federal agents to investigate and prosecute.